The present invention relates to a device for preparing a beverage from a food substance, such as a substance to be extracted and/or dissolved, contained in a capsule. More particularly, the invention relates to such a device comprising an improved piercing and injection element. The invention also relates to a method for improving the wetting or dissolution of a substance contained in a capsule.
The use of predetermined, prepackaged servings in capsule form containing a substance to be extracted, such as ground coffee, or a substance to be dissolved, such as chocolate products for preparing beverages, has many advantages, including facilitating the operations of preparing the beverage, ensuring relatively clean preparation, and controlling a relatively constant amount and quality of the beverage prepared.
The principle of extraction or dissolution of substances contained in the closed capsule typically consists in enclosing the capsule in a closed chamber of a preparation device, piercing one face of the capsule, injecting a quantity of hot water under pressure into the capsule so as to create a pressurized environment inside the capsule in order to extract the substance or dissolve it, then discharging the substance extract or dissolved substance through an opposite face of the capsule which, in contact with projecting parts of the device, opens under the effect of the internal pressure.
Devices for implementing this principle have already been described, for example in patents CH 605 293 and EP 242 556. According to these documents, the device comprises a housing for the capsule and a piercing and injection element in the form of a hollow pointed part comprising, in its distal region, one or more liquid injection orifices. The pointed part has a dual function in that it opens the upper part of the capsule, on the one hand, and constitutes the channel for water to enter the capsule, on the other hand. To improve the extraction and/or dissolution of the substance contained in the capsule, it has also been envisaged to equip these devices with several pointed parts each performing the abovementioned dual function, as described in document EP 1 203 554.
A first drawback of such devices lies in the fact that, because they are so small, the liquid injection orifices in the pointed part tend to become quickly blocked due to the scale in the water or contact with the substance, particularly when the capsule is not removed from the apparatus immediately and the piercing element is not rinsed after use, which affects the performance of the device. In particular, the flow becomes less regular and the jet becomes slower over time. This affects the conditions of extraction, the dissolution of the substance and, for example, the production of foam.
It would therefore be convenient to have a device that solves these problems.
Secondly, in the devices of the prior art, the method of wetting is based on the production of one or more discrete jets directed in a preferential direction. A single, discrete directed jet is often not enough to wet or dissolve a mass of substance contained in a capsule. Furthermore, a single jet creates a preferential path and forms holes in the mass of substance without however wetting or dissolving it completely. It is therefore usual to use several jets each directed in different directions. However, such a wetting or dissolution method is not entirely satisfactory because preferential paths are still created.
There is therefore a need for a method that wets or dissolves the substance more satisfactorily, without creating preferential paths but while maintaining the speed of the jet necessary to properly wet or dissolve the substance and, as appropriate, cause it to foam.